Conclusion and Outlook

Water injection has been proven to be a very promising technology to improve the efficiency of downsized turbocharged spark-ignition engines, overcoming the limiting factors in terms of knock phenomena and excessive turbine inlet temperatures, and extending the engine map range with stoichiometric operations. Several studies found in literature illustrate the potential of water injection and its limitations with conventional applications of indirect and direct water injection, also combined with additional technologies aimed to improve engine efficiency, such as Miller valve strategy, increased compression ratio and EGR.